Trends and Surveillance

Each year in the United States, RSV leads, on average, to approximately—

  • 2.1 million outpatient visits among children younger than 5 years old1
  • 58,000 hospitalizations among children younger than 5 years old2
  • 177,000 hospitalizations among adults 65 years and older3
  • 14,000 deaths among adults 65 years and older3

In the United States and other areas with similar climates, RSV infections occur primarily during fall, winter, and spring.

1Hall CB, Weinberg GA, Iwane MK, Blumkin AK, Edwards KM, et al. The burden of respiratory syncytial virus infection in young childrenexternal icon. New Engl J Med. 2009;360(6):588-98.
2Rha B, Curns AT, Lively JY, et al. Respiratory Syncytial Virus–Associated Hospitalizations Among Young Children: 2015–2016external icon. Pediatrics. 2020;146(1):e20193611
3Falsey AR, Hennessey PA, Formica MA, Cox C, Walsh EE. Respiratory syncytial virus infection in elderly and high-risk adultsexternal icon. New Engl J Med. 2005;352(17):1749-59.

RSV Seasonal Trends

CDC analyzes data on RSV activity at the national, regional, and state levels, collected by a surveillance system called the National Respiratory and Enteric Virus Surveillance System (NREVSS).

For 2016 to 2017, the RSV season onset ranged from mid-September to mid-November, season peak ranged from late December to mid-February, and season offset ranged from mid-April to mid-May in all 10 U.S. Department of Health and Human Services (HHS) regions, except Florida. Florida has an earlier RSV season onset and longer duration than most regions of the country (see figure).

Seasonal patterns remain consistent with previous years.

Surveillance Systems

CDC collects information on RSV laboratory detections in the United States using the National Respiratory and Enteric Virus Surveillance System (NREVSS). This is a voluntary, laboratory-based surveillance system established in the 1980s to monitor trends in several viruses, including RSV. NREVSS tracks the number of RSV tests that are done by participating laboratories and the proportion that are positive, by specimen type, location, and when they were collected. Serotyping, demographic data, and clinical data are not reported. Data from NREVSS provides information to public health officials and healthcare providers about the presence of RSV in their communities.